La Crosse County Water Quality: 3 Cities Ranked by the Records
La Crosse County, Wisconsin: 3 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
Highest result for each contaminant
One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.
Perfluorooctanesulfonic acid (PFOS)Detected in 1 system of 3 tested4.0 ng/L federal MCL (2024) · US EPAHighest5.5 ng/L
- LA CROSSE WATERWORKS5.5 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
Perfluorooctanoic acid (PFOA)Detected in 1 system of 3 tested4.0 ng/L federal MCL (2024) · US EPAHighest5.1 ng/L
- LA CROSSE WATERWORKS5.1 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 3 tested10 ng/L federal MCL (2024) · US EPAHighest8.4 ng/L
- LA CROSSE WATERWORKS8.4 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
Lead (90th percentile)Detected in 2 systems of 3 tested15 µg/L federal action level · US EPAHighest10.9 µg/L
- LA CROSSE WATERWORKS10.9 µg/LMonitoring period: 2025–2025
- HOLMEN WATERWORKS2.78 µg/LMonitoring period: 2023–2023
- ONALASKA WATERWORKSNot detectedMonitoring period: 2023–2023
Perfluorobutanesulfonic acid (PFBS)Detected in 2 systems of 3 tested2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest15 ng/L
- LA CROSSE WATERWORKS15 ng/LSample date: 2023-05-23 to 2024-05-06
- ONALASKA WATERWORKS4.2 ng/LSample date: 2023-01-10 to 2023-07-11
- HOLMEN WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
Perfluorohexanoic acid (PFHxA)Detected in 1 system of 3 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest3.7 ng/L
- LA CROSSE WATERWORKS3.7 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
Perfluorobutanoic acid (PFBA)Detected in 1 system of 3 testedNo federal or state limit; shown for transparencyHighest21 ng/L
- LA CROSSE WATERWORKS21 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKSNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
Perfluoropentanoic acid (PFPeA)Detected in 2 systems of 3 testedNo federal or state limit; shown for transparencyHighest4 ng/L
- LA CROSSE WATERWORKS4 ng/LSample date: 2023-05-23 to 2024-05-06
- HOLMEN WATERWORKS3.3 ng/LSample date: 2023-10-11 to 2024-04-04
- ONALASKA WATERWORKSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-10 to 2023-07-11
23 substances tested, none detected in any systemShow
Tested in these 3 systems: HOLMEN WATERWORKS, LA CROSSE WATERWORKS, ONALASKA WATERWORKS
- 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
- 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
- 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
- 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
- 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
- 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
- Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
- Lithium
- N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
- N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
- Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
- Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
- Perfluoro-3-methoxypropanoic acid (PFMPA)
- Perfluoro-4-methoxybutanoic acid (PFMBA)
- Perfluorodecanoic acid (PFDA)
- Perfluorododecanoic acid (PFDoA)
- Perfluoroheptanesulfonic acid (PFHpS)
- Perfluoroheptanoic acid (PFHpA)
- Perfluorononanoic acid (PFNA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.
0of 3 cities above the 15 µg/L action level
Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.
Lead in WisconsinLargest water systems
Frequently asked
How does La Crosse County tap water compare across cities?
PurityMap ranks 3 cities in La Crosse County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Onalaska's main water system: ONALASKA WATERWORKS · PWSID WI6320327 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.
How many La Crosse County cities have PFAS above the federal limit?
1 city of 3 had at least one regulated PFAS (PFOA, PFOS or PFHxS) measured above the 2024 federal limit in EPA's UCMR 5 testing, including La Crosse (PFOS 5.5 ng/L). PFAS were detected at any level in 3.
Is there lead in La Crosse County tap water?
Utilities report lead as a 90th-percentile result from home taps. 2 of 3 La Crosse County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.
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